ASTM International Committee F01 on Electronics has begun work on a proposed new standard, WK5616, Test Method for Measuring Micropipe Density in Silicon Carbide Substrates. According to Ejiro Emorhokpor, characterization engineer, II-VI Inc., the new standard will prove to be beneficial in several ways.

Labs that measure and count micropipes will be able to look at the industry baseline for the micropipe density, and will be able to interpret their results more accurately, with the proposed standard, says Emorhokpor, a member of Subcommittee F01.15 on Compound Semiconductors. The industry as a whole will benefit from knowing how to interpret reported results. Labs that are looking at instituting this test method will have a practical example of how to develop a technique that will be accurate, with well-documented results.

Emorhokpor feels that customers also will be well-served by the proposed standard. If customers request a micropipe specification, they need to be sure that companies are going to give them the product that meets that specification independently of their own test methods, says Emorhokpor.

Micropipes are tunnels or pipes of several microns in diameter that run the length of SiC crystals. Micropipe density is an important feature of device performance and production yield, but no documented method for micropipe defect counting is currently available. Different labs are using various undisclosed techniques for counting these defects, but there is a need to know the disparity in the micropipe density results from the diverse methods now employed in the industry, says Emorhokpor.